I am already aware of the right hand rule to determine the direction of torque. I am a bit confused however regarding the sign convention used during this process.
If the torque is into the plane, will it be taken as positive or negative?
I also know that a counter clockwise torque is taken as positive torque. Can someone please help me link these two concepts together?
I will give an instance where I am having trouble – till now I was taking the torque into the plane as positive torque; however when a body rolls down an inclined plane and I take the torque about the centre of mass, friction actually provides a torque out of the plane even though it rotates it counterclockwise.
Any help is appreciated!!
Best Answer
The use of the words clockwise and anticlockwise also require a statement about the viewing direction.
Imagine that you want to find the torque due to a force $\vec A$ about the origin as shown in the diagrams below.
In both cases the torque $\vec \tau$ is given by $$\vec d \times \vec A = d\hat x \times A \hat y = dA\hat z$$ ie in the positive z-direction although in the left hand diagram it is an "anticlockwise" torque and in the right hand diagram it is a "clockwise" torque.